Apparatus for testing balls



Aug. 8, 1950 T w, w. cUsHMAN ErAl. 2,517,545v

APPARATUS FOR TESTING BALLS Filed Febl 2o,v 1946 2 sheets-sheet 1 ,YL/Mud Koren w. w. cUsHMAN ETAL 2,517,545

T APPARATUS FOR TESTING BALLS Aug. 8, 1950 2 Sheets-Sheet 2 Filed Feb. 20, 1946 Patented Aug. 8, 1950 UNI TED- S'TATES PATENT OFFICE l 2,517,545 APPARATUS. Fon 'iiisrino4 BALLS Walton W. Cushman, Webb (Lity, Mo., and Samuel Koren, Silver Spring, Md.;fsaid Koren assigner tol the United States of Americaas represented bythe Secretary of. War

Application February 2.0, 194.6,i Serial No. 649,105 31'Clai'rns. (fCl. '1S-13") (Granted underV the, act of March. 3, 1883, asl` The invention described -hereint if patented, be manufactured and used by or for the Govremment for governmental. purposes., without the payment. to us of. any royalty thereon.

'lghis invention relates to an apparatus for testingf ballsLandinore particularly, to an apparatus iertesting the; durability/,and resiiiency of bans,

.imally subject: to impact,v such as table tennis halls.; Y

An-.Qblect of` this invention isto provide an apparatus. for. testing a-plurality of balls. simultuanenusly'by subjecting such balls in succession to impact. treatment similar to that received during actual game so that aiter a given period of ofj testing, each or the paus will have. received the same treatment, it would have received over the. same period of timeof actual play.

Itisv a-.further object of this invention to pro.- vidaan. apparatus for testirigballs, normally subinetto periodic impact, having means for` periodi-.- cally placing, the ball. in ilight and impacting the ball at time. intervals withV forces corresponding tnvforces, of actual use.

Still, another objectof this invention is to provide. an apparatus for testing. the durabiiity and resiliency of.. table tennis balls providing means for impelling, ballsundjerv centrifugal force against one or more backboards. and means for automatically recirculating the balls to repeat the cigale at time. intervals correspendingl to table tennis volley.

Other objects and" advantages of the present inyentionA will appear in the following detailed description and particularly will` bei pointed out theappend'edclaims, reference being had to they accompanying drawings forminglpart of; this specification, and'in which:

AEi'gure lis-an elevational viewof the apparatus embodying this invention and showing` its mode oiioperationz.

Figure 21s a plan view of parto-f the apparatus showing the major part of*` the ball-impelling mechanism;`

Figure 3; a sectional viewl or the impellmg mechanism taken on line4 3-3 ot' Figure 2,l and with. part ofthe mechanism shownV in elevation;

FigurenV is an' exploded View ofa fragmentary detail; show-ing the discharge mechanism of? the tunnelling mechanism; and

Figure 5: is aA sectional' View taken on line 5-.5 cffEigure 1, showing i the. position. of. the deflect.- ingfhcardrelative .to theimpelling mechanism.

Referring; to.- the.. drawings,` andV particularly l; lf represents generally. the impelling mechanism; for; ,impellngi balls. successively at.

" amended April 30, 192.8; 370 O... G. 757) periodic intervals substantially horizontally throughspace as indicated by the ball inllight, in position 2. The balls strike the board-1 or plate 3- and rebound toward the delecting board 4L which bounces the ball into net E, from whence the balls fall freely, indicated by arrow 6, into the impelling mechanism to repeat the cycle.

The impelling mechanism coni-prises theyhopper l which is suitably xed to a horizontally extend@- ing hollow impelling tube 8.,. for feeding the balls through opening 9 into the-tube 8. As. shown, the tube 8 has fixed thereto a tubular guidev le, shown in Figure 3, surrounding opening 9;, to which the hopper 'i is iixed,` but it is within the. scope. of this invention to fasten the hopper 1- to tube 8 by any suitable means tofeed balls through opening 9 intothe tube.

The tube 8 is fixed to a, supporting: bracket` Il which is adapted to; be fastened by` means of set'.- screws. l2 to a motor shaft I3 driven by a conventional synchronous motor; for example, an 1800-R. P.y M. motor housed in housing i4. The motor housing i4 may be provided with support.- ing legs iito carry the impelling assembly. rllhe impelling assembly may be iixed permanently to f a table. or. iloor, or may be bolted by bolts i6.. to

aplatform for portability. Asseen inthe draw'- ings,` the bracket` Il, motor shaft I3v and hopper l are. in axial. vertical alignment so that as the motor is driven,A the impelling` tube8 and` hopper l are.. rotated. as a unit about the vertical axis of the hopper.

As. shown inFigures 2 and 3,A the impelling tube 8 is provided with a bailie Il to direct the balls toward the. discharge end.. the. rightv end of the tube as seen in Figures 2 and 3.` As the tube 8 rotates, abouta vertical axisy at 1.800 R. P. the series of balls are carried by centrifugal force to the. discharge mechanism. L8, to be described hereinafter. The opposite end of, tube 8 is lled with leadwool I9. for static balance andthe end is. closed off by a threaded retainer plug 2!! which is locked in. position by any suitable means; for example, by means off the Cotter pin- 2| passing through openings. in the tube and a groove, 20.1 in the plug 201 The discharge mechanism. l'8 consistsof a cut,- away sleeve ZI, provided with a lateral' opening 22j and' rotatable about its.V own axis. and housed in a, short vertically extending tubular member 2.3 weldedor otherwise4 securely iixed to the-.horizontal tube. 8.. The tubular. member 23 is provided with. an inlet opening; 24 (shown inV Figure 3). communicating with the tube il: andZ a. diametrically i'ipposite.` outlet openingV 25.. The lower end of the sleeve 2| is closed off by a disc 26 which provides a receptacle therewith for a single ball. The bottom 27 of tubular member 23, as shown in Figure 3, provides a bearing on which the sleeve 2| with disc 26 areiree to rotate as a unit. A vertically extending shaft 28 is fixed to the center of the disc 26 and extends downwardly through a bearing sleeve 29 forming an extension of the bottom 21. To the lower end of shaft 28 is fixed a sprocket 291 which is driven by a sprocket chain 30, actuated by a stationary sprocket 3|, rigidly aiilxed to the motor housing |4 and non-rotatable.

The board or plate 3 has an adjustable pivotal connection 32 to a suitable supporting stand 33 so that the angle of board 3 can be varied to vary the angle at which balls strike and rebound therey from. The board 3 is fixed in adjusted position by a wing nut 321. The stand 33 is movable to adjust its position. The deilecting board 4 is similarly pivotally and adjustably connected to supporting stand 34 by means of a, wing nut 341. The stand 34 is offset, as shown in Figure 5, so as not to interfere with balls discharged from the impelling mechanism The angle of the board 4 may be adjusted and xed in adjusted position by wing nut 341 to vary the angle of striking and bouncing therefrom. The stand 34 is movable for adjustment of position of board 4. The fabric net 5 is suitably supported on a wall or on a stand in an adjustable manner. The net 5 deadens the ilight of the ball and insures that the balls are directed into the hopper l.

As the balls circulate and recirculate through the apparatus, they strike board 3 at a. low angle of incidence and rebound at almost 90 from the board and receive a heavy impact, thus simulating a, head-on paddle stroke in a table tennis game. The balls strike board 4 at a large angie of incidence (low angle to the board) and rel ceive a lighter impact and bounce, simulating an impact of a ball bouncing on a tennis table at a low angle. The fabric net 5 deadens the ball, without impact, for dropping into hopper 'i without any additional impact or with only inconsequential impact. from the discharge mechanism i8 by centrifugal force, receives little, if any, impact at that point. Thus, as the apparatus is operated to impe1 and impact and bounce a succession of balls under test, the durability and resiliency or bouncing ability of the balls can be studied. If any ball should become defective during the test run, it willnot rebound or bounce, or will rebound or bounce inaccurately, from boards 3 or 4 and will fall to the oor as denoted, for example, by the arrow 35. Thus, if fifteen balls are placed in the machine for testing together, the number of balls falling to the floor over a given period of time will be a measure of the durability and resiliency and bouncing quality of the balls. Also, a number of balls of different manufacture (for example, fifteen balls) can be tested simultaneously to determine which is the most durable.

In operation, as the balls are fed into hopper l, they move down to the discharge end of tube 8 by centrifugal force and abut each other in a single line, as shown by dotted lines in Figure 3. As the tube 8 rotates, due to the sprocket and chain mechanism 291, 3U and 3|, sleeve 2| rotates about its own axis in synchronism with the rotation of tube 8 and when the cut-out 22 of sleeve 2| is in alignment with tube 8 the outermost ball is forced into sleeve 2i by centrifugal action. Continued rotation of tube 8 and sleeve 2| will eventually result in sleeve 2| rotating to a position 4 wherein cut-out 22 is in alignment with outlet opening 25. At that moment, the ball in sleeve 2| is ejected under centrifugal force toward board 3 while the remaining balls in tube 8 are retained by the sleeve 2|; Thus the sleeve 2| acts as a valve to release a ball periodically in synchronism with the rotation of tube 8.

In the particular embodiment illustrated, sprocket 291 has a four-to-one ratio to sprocket 3| and thus for every four revolutions of tube 8 the sleeve 2| will rotate once to discharge a single ball. If the motor used is an 180o-R. P. M. motor, making 30 revolutions per second, the sleeve 2| will make 'l1/2 revolutions per second, thus discharging balls at the rate of 'l1/2 balls per second. Thus the balls will be discharged and returned to the hopper at the rate of 'l1/2 balls per second, and therefore two seconds will be required to complete the cycle for the fifteen balls. If the machine is operated continuously, each and every ball will be discharged and returned to complete a cycle every two seconds. Thus, every two seconds a ball will be impelled to strike board S, rebound to deecting board 4, bounce to net 5, drop into the hopper l, and move to its initial position. In the case of table tennis balls, the ball impinging against board 3 can'be likened to a paddle striking the ball almost headon, and the ball impinging against board 4 atl-a low angle of approach can be likened to the ball striking and bouncing oi a tablev tennis table. Then when the ball again impinges against board 3 two seconds later, it can be likened t0 the opponents paddle stroke, and when it vagain bounces oif board 4, it can be likened to the next succeeding bounce, and so on.

Thus it is apparent that the apparatus of this invention has means for impacting a ball heavily head-on and subsequently lightly a glancing blow to correspond to a paddle stroke and a bounce, and that the apparatus can be timed to correspond to paddle strokes and bounces of an ac tual game; for example, a paddle stroke'every two seconds for each ball, which may be consid- The ball, being impelled ered the approximate time which ordinarily elapses between strokes in a, table tennis game. It is apparent that a method for testing balls has been provided which includes the steps ofimpacting balls heavily and/or lightly and -at ysuch time intervals to simulate actual playing condi`- tions, inherent in games such as table tennis, ten-l nis, squash, etc. 1

It is of course obvious that by changing the sprocket ratio of sprockets 291 and 3| the time interval can be increased or decreased as 'desired. It might be preferable 4to adjust the tim'- ing for a time interval of one second to simulate conditions in a fast table tennis game. Also, .if a different motor, for example a SOO-R. P. M. motor, is used the sprocket ratio can be changed to a two-to-one ratio to allow fora discharge of one ball for every two revolutions of tube v8, or again, 71/2 balls per second, to maintain the twosecond time interval when fifteen balls are used.

For the purpose of testing, a discharge velocity of approximately feet per second has been found desirable. To effect this speed with an l800-R. P. M. motor, the horizontal distance from the axis of the hopper I to the discharge-outlet should be approximately 91/2 inches. For a'900. R. P. M. motor this distance should be about 19 inches. It is, of course, within the scope of this invention to use higher or smaller discharge velocities by changingthe motor speed and/orl the horizontal distance between the axis of the hopper and the discharge outlet.

Though the above description refers to using fteen balls in the machine, it is within the scope of this invention to test a greater or lesser number at one time.

It is evident that an apparatus has been devised which subjects a ball to almost the exact type of treatment it normally would receive during a game of table tennis as to paddle stroke and table bounce. Also, the timing of impacts is such as to correspond to that of table tennis so that op erating the apparatus for any given period will correspond to a playing time of the same period. Thus, operating the apparatus for one hour will correspond to each balls being subjected to one hour of playing time. When fifteen balls are tested, the operation for one hour is equivalent to fifteen games, each of one hours duration.

Although the apparatus illustrated is arranged With the impelling mechanism I having a vertical axis of rotation, it is obviously Within the scope of this invention to arrange the impelling mechanism I to rotate about a horizontal axis. In this embodiment, the opening 9 would be in a vertical plane instead of in a horizontal plane and a stationary chute could be used, instead of hopper l, to direct returning balls into opening 9.

Though the above description is with special reference to testing table tennis balls, it is to be understood that other types of balls, which receive impact during play, may be tested. As in dicated above, the time interval for a cycle can be varied to conform to the time conditionsofl the game involved. Also, the time between impacts against board 3 and board 4 can be varied by adjusting the positions of stands 33 and/or 34. Thus, adjustments can be made to conform more nearly to the time intervals between different impacts of actual play. Also, the material of board 3 and board 4 can be varied, depending on the type of ball being tested. For example, for table tennis balls, board 3 may consist of rubbercovered plywood, and board 4 may consist of plywood. Also, if only one impact is desired during each cycle, board 4 can be eliminated and net 5 moved to receive and guide the ball into hopper 1. It is to be understood that the apparatus is designed and operated to subject a ball to treatment over a period of time as closely as possible to the kind of treatment it would receive during the same period of time of actual play. For example, one hour of continuous operation of the machine would be equivalent to one hour of playing time for each of the balls being tested.

While the invention has been Idescribed in more or less detail, it is not to be limited thereby, as changes may be made in the form, arrangement and construction of parts, and equivalents may be substituted, Without departing from the spirit and scope of the invention as claimed, the form hereinbefore described being merely a preferred embodiment thereof.

We claim:

l. In an apparatus for testing the durability and resiliency oi' balls, the combination of a tube for receiving the balls, means for rotating said tube in a horizontal plane about an axis at right angles to the axis of the tube whereby the balls are directed to, and discharged from the outer end of the tube by centrifugal force, a rotatable discharge valve at the outer end of the tube for controlling the direction of discharge of the balls, and means for rotating said valve in synchronization with the rotation of said tube.

2. In an apparatus for testing the durability and resiliency of balls, the combination of a tube for receiving the balls, means for rotating said tube in a iiaorizontal plane about an axis at right angles to the axis of the tube whereby the balls are directed to, and discharged from the outer end of the tube by centrifugal force, a rotatable discharge valve at the outer end of the tube for controlling the direction of discharge of the balls, means for rotating 'said valve in synchronization with the rotation cf said tube, means for impacting discharged balls, and means for returning said impacted balls to the tube.

3. In an apparatus for testing the durability and resiliency of balls, the combination of a tube for receiving the balls, means for rotating said tube in a horizontal plane about an axis at right angles to the 4axis of the tube whereby the balls are directed to, and discharged from the outer end of the tube by centrifugal force, a rotatable discharge valve at the outer end of the tube for controlling the direction of discharge of the balls, means for rotating said Valve in synchronization with the rotation of said tube, means for impacting discharged balls, and means for returning said impacted balls to the tube, said means including a funnel communicating with the interior of the tube at its center of rotation.

WALTON W. CUSHMAN. SAMUEL KOREN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,198,300 Watkins Sept. 12, 1916 1,636,234 Klopsteg July 19, 1927 FOREIGN PATENTS Number Country Date 486,533 Great Britain June 7, 1938 548,424 Germany Apr. 12, 1932 

